Choke control



J. L. MOTT oHoKE CONTROL Feb. '5, 1935.

Original Filed Jan. 25, 1952 /4 rra/vef CII Patented Feb. 5, 1935 1,990,083 CHOKE CONTROL John L. Mott, St. Helens, Oreg., assignor to Carl` E. Swan, Portland, Oreg.

Application January 23, 1932*, Serial No. 588,436

Renewed August 15, 1934 4 Claims.

This invention relates generally to internal combustion engines with particular reference to the automobile type of engine.

The main object of this invention is to provide an automatic choke control for an internal combustion engine which will lower the richness of the mixture as soon as the temperature of the engine rises sufficiently to permit this being done.

The second object is to provide a choke controlA which will prevent crank-case dilution, the washing of lubricant from the cylinder walls, and the fouling of spark plugs ordinarily occasioned by running the engine with the choke closed more than is necessary, due either to inexperience or carelessness on the part of the operator.

These, and other objects, will become more apparent from the specification following as illustrated lin the accompanying drawing, in which:

Fig. 1 is a iront elevation of the device.

Fig. 2 is a section through the device showing the parts in the stopped position of the engine.

Fig. 3 is a fragmentary View showing the position of the parts as the engine turns over under the power of the self-starter.

Fig. 4 is a view similar to Fig. 3, but showing the` engine running under its own power in a position of partial choke.

Fig. 5 is a section taken along the line 5-5 inl Fig. 3.

Fig. 6 is a fragmentary view illustrating a modii'ied form of thermal control for the device.

Fig. '7 illustrates a simple modification of the device in which the partial choke setting is adjustable.

Similar numbers of reference refer to the same or similar parts throughout the several views.

Referring in detail to the drawing, there is shown a common form of exhaust manifold 10, an intake manifold 11 of a common form of automobile engine, a carburetor 12 and a buttery choke valve 13 which is normally controlled by a` rod 14 on Whose end is a choke button 15 usually mounted on an instrument board 16.

Referring more particularly to my invention, same will be seen to consist of a pneumatic cylinder lG--A one end of which is connected by means of a pipev 17 `to the intake manifold 11. Within the cylinder 16 is a piston 18 whose rod 19 guides in the end 20 of the cylinder 16. To the end of the rod 19 is attached 'a link 21 which is double and is provided at its extreme end with a latch pin 22. The link 21 is urged toward a straight line position with relation to the rod 19 by means of a spring 23.

(Cl. 12d-124) The cylinder 16-A is mounted under the upper end 24 of a case 25 near the lower end of which is pivotally mounted an arm 26 on the pin 27. .The arm. ,26 isdouble and is provided with an arcuate slot 28 on onev sidey ofk which are they notches 29 and 30. The latch pin 22 passes throughtheV slot 28 which extends through both sides of the arm 26.v Between the sides of the arm 26 issecured a loi-metallic strip 31 having abent end 32 which extends `around the notched side of the slot 28 for aV purpose which will be explained later. The lower end 33 o f the arm 26 projects through a slotv` 34m the bottom 35 of the casing 25.V To the end 33 is attached a connect-` ing rod 36 whose lower end is joined to the lever 37 on the shaft 38 of the butte'ry valve 13. A spring 39 is placed on the under side of the lugv 40 around the rod 36 for the purpose of urging it downwardly in a direction rwhich will open the choke. The lug 40 is stationary and the rod`36 is slidable within the lug. l

y The operation of this form of the device` is as follows: Assuming the parts to bein a position v shown in Fig.2; that is, when the -engine is not running, and in which the latch 22 engages the notch 29 when the choke button 15- is pulled Aout the full distance, the operator now turns the motor over with .the starter. It will be seen that the suction produced within the cylinder l--A` will raise the piston 18, and through the link 21 pull the arm 26 to the position shown in Fig. 3. As soon as the motor starts to operate under its own power and its speed increases the vacuum it will raise the arm 26 still higher until the latch 22 slips off of the notch 29 and engages the notch 30, as shown in Fig. 4. 'As the motor warms up and the element 31 begins to bend under the inluence of the heat, the bent end 32 moves toward the latch 22, causing it to disengage the notch 30, at which time the link 21 will assume the position shown in dotted lines in Fig. 2, in which the choke button 15 is pushed way in under the influence of the spring 39.

In the form of the device shown in Fig. 6, a spiral thermal element 41 is mounted on the arm 26 and is employed to rotate a shaft 42 which carries an eccentric cam 43 whose position determines the distance the p'm 22 can rise in the slot 28 and therefore controls the closing action of the choke in direct relation to the temperature of the motor.

In the form shown in Fig. 7, the choke wire 44 is attached directly to an arm 45 on the shaft 38 of the butterfly valve 13. The arm 45 is urged toward an open position by the spring 46. A

latch 47 is mounted on the end of a bi-metallic spring element 48 which is secured to a block 49. The block 49 is adjustably mounted on the slide 50 under the control of the adjusting screw 51. In this form of the device, the operation isi identical with that of the' form previouslyfdescribed, except that the setting of the intermediate choke position is made adjustable.

While I have described the operation of this device as requiring the manual use of the choke button 15, it is obvious that this manual movement is not actually required unless there should be a failure in the parts of the automatic device. In actual practice the driver merely steps on the starter producing a suction in the cylinder 16--A which pulls up the piston 18 and, by reason of the fact that the pin 22 is in engagement with the notch 29, the arm 26 is drawn to the full choke position, which is identical with the one it would assume if the button 15 were pulled out manually.

I claim:

1. A choke control for gasoline motors, having in combination a choke control valve, spring means for urging said valve toward a lean mixture position, latch means for holding said valve in a richmixture position, means for releasing said latch after the operation of the self-starter, a second latch for holding said valve in a partial choke position, and a thermostat arranged to release said second latch and to permit said valve to move under the action of said spring.

2. A choke control for gasoline motors, having in comb-ination a choke control valve, latch means for holding said valve in a full choke and partial choke positions, means for releasing the full choke latch when said motor is running under its own power, and thermostat means for releasing said partial choke latch as the temperature of said motor rises.

3. A choke control for gasoline motors, having in combination a choke control valve, latch means for holding said Valve in a full choke position to which it is moved manually, a second latch means for holding said Valve in a partial chokeA position to which it is moved when said motor is turned over by a starter, a thermostatically operated release for said second latch means, and

spring means for urging said valve toward a lean mixture position.

4. An automobile having a gasoline motor including a self-starter and having a carburetor including a choke valve for varying the richness of the fuel mixture, in combination with a control mechanism for said choke valve comprisingv a manually. operated choke control, an automatic control comprising a case, an arm hinged Within said case, a connecting rod between one end of said arm and said choke valve, a spring for urging said connecting rod downwardly, said hinged arm having an arcuate slot formed therein having a lateral full choke notch at its lower end of one side thereof and an intermediate partial choke notch in the same side thereof, a pneumatic cylinder communicating with the air intake line of the engine, a piston within said cylinder having a piston rod projecting therefrom, said piston rod having a link depending therefrom together with a spring for urging said link toward a straight'line position with relation to said piston rod, the lower end of said link having a latch pin therein occupying the slot in said arm, a bi-metallic strip mounted on said arm having one end thereof adjacent to said intermediate notch and adapted to have its end move across said intermediate notch for the purpose of releasing said latch pin when the temperature or" the motor rises to a predetermined position whereby said latch pin will normally occupy the uppermost portion of said slot when the motor is warm and running and whereby the manual closing of said choke will cause said latch pin to engage said lowermost notch in the slot arm and the operation of the motor starter will cause said piston to rise a portion of its travel and hold said arm in a full choke position until the motor operates under its own power whereon an increased suction in said piston causes a disengagement of said latch pin with the lowermost notch and its engagement with the intermediate notch, and a given rise in temperature of said bi-metallic element will free said latch pin from said intermediate notch and permit said choke operating spring to open same to a minimum choke position.

JOHN L. MOTT. 

